Ultrasound imaging probe

Abstract

Ultrasonic Imaging Probe The present description relates to an ultrasonic imaging probe (100) comprising a plurality of elementary ultrasonic transducers (111) arranged in a matrix in rows and columns, wherein the elementary transducers (111) are distributed into several elementary groups (113) each comprising a plurality of transducers (111), the probe comprising, for each elementary group (113), an analog micro-beamforming circuit (123) individually connected to each transducer (111) of the group (113), and adapted to provide an analog signal generated by delay and summation of analog response signals of the elementary transducers (111) of the group (113), wherein each elementary group (113) consists of a set of adjacent elementary transducers (111), said set having at least one dimension, in the direction of the rows, different from one dimension, in the direction of the columns.Figure for the summary: Fig. 2.

Description

Title of the invention: Ultrasound imaging probe Technical field

[0001] The present description relates to the field of ultrasound imaging, and more particularly relates to an ultrasound imaging probe intended to be connected to an external control and processing system via a cable, the probe integrating a plurality of ultrasound transducers and electronic circuits for controlling these transducers. Prior art

[0002] Various architectures of ultrasound imaging probes have already been proposed.

[0003] It would be desirable to improve at least in part certain aspects of known ultrasound imaging probes.

[0004] We are more particularly interested here in the production of an ultrasound imaging probe comprising analog circuits adapted to implement micro-beamforming functions, for example for the implementation of ultrafast acquisition scenarios. Summary of the invention

[0005] One embodiment provides an ultrasound imaging probe comprising a plurality of elementary ultrasound transducers arranged in a matrix in rows and columns, in which the elementary transducers are distributed into several elementary groups each comprising a plurality of transducers, the probe comprising, for each elementary group, an analog microbeamforming circuit connected individually to each transducer of the group, and adapted to provide an analog signal generated by delay and summation of analog response signals of the elementary transducers of the group, in which each elementary group consists of a set of adjacent elementary transducers, said set having at least one dimension, in the direction of the rows, different from a dimension, in the direction of the columns, or in which the elementary transducers each have an elongated shape in the direction of the rows or columns, and each elementary group consists of a set of adjacent elementary transducers, said set having a generally square shape.

[0006] According to one embodiment, each elementary group comprises a number of elementary transducers different from an integer squared.

[0007] According to one embodiment, the elementary groups have im- bricked.

[0008] According to one embodiment, the elementary groups have nested head-to-tail L shapes, or nested head-to-tail F shapes.

[0009] According to one embodiment, the elementary groups have nested cross shapes.

[0010] According to one embodiment, each elementary group is made up solely of adjacent elementary transducers of the same row or of the same column of the matrix of elementary transducers.

[0011] According to one embodiment, each column of elementary transducers of the matrix of elementary transducers comprises several elementary groups each comprising a plurality of adjacent elementary transducers of the column, and / or each row of elementary transducers of the matrix of elementary transducers comprises several elementary groups each comprising a plurality of adjacent elementary transducers of the row.

[0012] According to one embodiment, each elementary transducer belongs to only a first elementary group consisting only of elementary transducers from the same row of the matrix of elementary transducers, and a second elementary group consisting only of elementary transducers from the same column of the matrix of elementary transducers.

[0013] According to one embodiment, each elementary transducer belongs to a single elementary group.

[0014] According to one embodiment, the probe comprises, for each elementary transducer, a specific reception circuit connected to an electrode of the transducer.

[0015] According to one embodiment, each transceiver circuit comprises an amplifier and a gain time adjustment circuit between said electrode of the transducer and an input terminal of the micro-beamforming circuit. Brief description of the drawings

[0016] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0017] [Fig.l] schematically and partially represents an example of an ultrasound imaging probe;

[0018] [Fig.2] schematically and partially represents an example of an arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment;

[0019] [Fig.3] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to an embodiment;

[0020] [Fig.4] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment;

[0021] [Fig.5] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment;

[0022] [Fig.6] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment;

[0023] [Fig.7] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment;

[0024] [Fig.8] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment;

[0025] [Fig.9] schematically and partially represents another example of embodiment of an ultrasound imaging probe according to one embodiment;

[0026] [Fig. 10] schematically and partially represents another example of an embodiment of an ultrasound imaging probe according to one embodiment;

[0027] [Fig. 1 1] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment; and

[0028] [Fig. 12] schematically and partially represents another example of arrangement of elementary transducers of an ultrasound imaging probe according to one embodiment;

[0029]

[0030] . Description of the embodiments

[0031] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0032] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, the various applications that the described ultrasound imaging probes and systems may have have not been detailed, the described embodiments being compatible with the ap usual applications of ultrasound imaging probes. In addition, the properties (frequencies, shapes, amplitudes, etc.) of the electrical excitation signals applied to the ultrasound transducers have not been detailed, the embodiments described being compatible with the excitation signals usually used in ultrasound imaging systems, which can be chosen according to the application considered and in particular the nature of the body to be analyzed, for example according to the physiology of the tissues to be analyzed, and the type of information that one seeks to acquire. Similarly, the various processing operations applied to the electrical signals provided by the ultrasound transducers and read by the control circuit to extract useful information on the body to be analyzed have not been detailed, the embodiments described being compatible with the processing operations usually used in ultrasound imaging systems.Furthermore, the production of the ultrasonic transducers and the electronic circuits for controlling the transducers has not been described in detail, the detailed production of these elements being within the reach of those skilled in the art from the indications of the present description, using known techniques for producing ultrasonic transducers and electronic circuits.

[0033] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than electrical conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0034] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made unless otherwise specified to the orientation of the figures.

[0035] Unless otherwise specified, the expressions "about", "approximately", "substantially", and "of the order of" mean to within 10%, preferably to within 5%.

[0036] [Fig. 1] is an exploded view schematically and partially showing an example of an ultrasound imaging probe 100.

[0037] The probe 100 comprises a plurality of elementary ultrasonic transducers 111, and electronic circuits for controlling the transducers.

[0038] In operation, all of the probe's ultrasonic transducers are arranged facing a body of which an image is to be acquired. The electronic control circuits are configured to apply electrical excitation signals to the transducers, so as to cause the transducers to emit ultrasonic waves in the direction of the body to be analyzed. The ultrasonic waves emitted by the transducers are reflected by the body to be analyzed (by its internal and / or surface structure), then returned to the body to be analyzed. come to the transducers which convert them back into electrical signals. These electrical response signals are read by the electronic control circuits, then transmitted to an external processing device EXT (not detailed in the figure), for example a computer, via a connecting cable (not shown). These signals can be stored and analyzed by the external device to deduce information about the body studied. Note in [Fig.l], the transmission circuits, suitable for applying electrical excitation signals to the transducers, have not been shown.

[0039] The probe 100 is for example a portable probe intended to be positioned and, possibly moved, manually, on the body of a patient.

[0040] In the example of [Fig.l], the probe 100 comprises a plurality of elementary ultrasonic transducers 111 arranged in a matrix according to rows and columns. The elementary transducers 111 are for example all identical, apart from manufacturing dispersions. In [Fig.l], a matrix of 9*9 elementary transducers 111 has been shown. In practice, the matrix can comprise several thousand to several tens of thousands of individually addressable elementary transducers 111.

[0041] Each elementary transducer 111 comprises two electrodes (not detailed in the figure) making it possible to apply an electrical excitation signal to the transducer and to read an electrical response signal from the transducer.

[0042] The elementary transducers 111 are for example CMUT type transducers (micro-machined capacitive ultrasonic transducers), for example PMUT type transducers (piezoelectric micro-machined ultrasonic transducer), piezoelectric crystal or ceramic transducers, or any other type of ultrasonic transducers.

[0043] By way of example, the inter-transducer pitch is of the order of a few tens to a few hundreds of micrometers in the direction of the rows and in the direction of the columns. The embodiments described are however not limited to this particular case. In the example of [Fig. 1], the elementary transducers 111 have a square shape, the orthogonal sides of the squares being parallel respectively to the direction of the rows and to the direction of the columns, and the inter-transducer pitch being identical in the direction of the rows and in the direction of the columns.

[0044] In the example of [Fig.l], the elementary transducers 111 of the probe 100 are distributed into elementary groups 113 each comprising a square sub-matrix of n*n adjacent transducers. In the example shown, n is equal to 3. By way of example, each elementary transducer 111 belongs to one and only one elementary group 113.

[0045] The probe 100 further comprises an analog transceiver circuit 120, only partially shown in [Fig.l]. The analog circuit transmission-reception circuit 120 comprises, for each elementary transducer 111, an elementary reception circuit 121. The analog transmission-reception circuit 120 may further comprise, for each elementary transducer, an elementary transmission circuit (not shown), and a transmission-reception switch (not shown).

[0046] By way of example, the elementary transmission circuit is adapted to apply an electrical excitation signal to the elementary transducer 111 during a phase of transmission of an ultrasonic wave. The elementary reception circuit 121 is for its part adapted to condition and amplify an electrical response signal generated by the transducer 111 during a phase of reception of an ultrasonic wave. The transmission-reception switch makes it possible to connect an electrode of the elementary transducer 111 either to an output terminal of the elementary transmission circuit (during the phase of transmission of an ultrasonic wave), or to an input terminal of the elementary reception circuit (during the phase of reception of an ultrasonic wave).

[0047] The transmission circuit comprises for example a pulse generator having an input terminal intended to receive a logic control signal, and an output terminal connected, for example connected, to the output terminal of the transmission circuit. The input terminal of the pulse generator can be connected, for example connected, to an output node of a logic control circuit (not shown) of the probe. When the logic signal applied to the input terminal of the pulse generator is in a first state, the pulse generator provides a high level voltage on its output terminal, and, when the logic signal applied to the input terminal of the pulse generator is in a second state, the pulse generator provides a low level voltage on its output terminal. The output signal of the pulse generator corresponds to an excitation signal of the transducer 111, which can be applied directly to the electrode of the transducer.

[0048] In this example, the receiving circuit 121 comprises a receiving amplifier 121a, preferably a low noise amplifier (LNA), having an input terminal connected, for example connected, to the input terminal of the receiving circuit. The amplifier 121a is for example a linear amplifier. In addition, in this example, the receiving circuit 121 comprises a time gain adjustment (TGC) circuit 121b having an input terminal connected, for example connected, to an output terminal of the receiving amplifier 121a, and an output terminal connected, for example connected, to an output terminal of the receiving circuit 121. The circuit 121b is configured to apply a time-varying analog gain to the response signal of the transducer, during a receiving phase.More particularly, during a phase of reception of a return ultrasonic wave by the transducer 111, the gain applied by the circuit 121b to the response signal of the transducer increases progressively as a function of time, and therefore as a function of the depth of the explored zone, so as to compensate. the attenuation of the ultrasonic signal by the explored medium. As a variant, not shown, the time gain adjustment circuit 121b can be placed upstream of the amplifier 121a, between the input terminal of the reception circuit 121 and the input terminal of the amplifier 121a. In this case, the circuit 121b applies a progressive attenuation so as to homogenize the amplitude of the signal as a function of the exploration depth before amplification by the circuit 121a. In another variant, the gain adjustment function is implemented by the amplification circuit 121a itself (non-linear amplification).

[0049] The analog transmission-reception circuit 120 further comprises, for each elementary group 113 of ultrasonic transducers 111, an analog micro-beam-forming circuit 123 connected individually to each transducer of the group, and adapted to provide an analog signal corresponding to a sum of analog response signals of the elementary transducers 111 of the group.

[0050] More particularly, in this example, each micro-beamforming circuit 123 comprises, for each elementary transducer 111 of the group 113, a delay circuit 123a, i.e. n*n delay circuits 123a per circuit 123. Each delay circuit 123a has an input terminal connected, for example connected, to the output terminal of the reception circuit 121 of the associated elementary transducer 111, and an output terminal. Each circuit 123a is adapted to provide on its output terminal an analog signal corresponding to the analog signal applied to its input terminal delayed by a predetermined, fixed or adjustable delay. The delays introduced by the circuits 123a may be identical for all the elementary transducers 111 of the elementary group 113, or differentiated individually for each transducer.

[0051] Each micro-beamforming circuit 123 further comprises an analog summing circuit 123b comprising a specific input terminal per elementary transducer 111 of the associated elementary group 113, i.e. n*n individualized input terminals in this example, and a single output terminal. The input terminals of the analog summing circuit 123b are connected, for example connected, respectively and individually to the output terminals of the n*n elementary reception circuits 121 associated with the n*n elementary transducers 111 of the elementary group 113. The circuit 123b is adapted to provide, on its output terminal, an analog signal representative of the sum or superposition of the analog signals applied to its n*n input terminals.

[0052] The output signal of each micro-beamforming circuit 123 may be transmitted to the external control and processing device (EXT) in analog form via a single conductive wire. Alternatively, the probe may include a specific analog / digital converter (not shown) at the output of each summing circuit 123b, the output signals of the micro-beamforming circuits beamforming 123 then being transmitted to the outside of the probe in digital form.

[0053] As illustrated in [Fig.l], the electronic transmission-reception circuit 120 comprises one or more input terminals adapted to receive power supply and control signals P. The power supply and control signals P are for example transmitted from the external device via one or more conductive wires of the connecting cable electrically connecting the probe 100 to the external device.

[0054] The provision of the analog micro-beamforming circuits 123 in the probe 100 advantageously makes it possible to limit (divide by n*n) in the example of [Fig.l], the number of response signals to be transmitted at the output of the analog transmission-reception circuit 120 during a reception phase of an ultrasonic wave. All of the response signals generated by the micro-beamforming circuits 123 can be transmitted to the outside of the probe (before or after digitization), for example to implement ultrafast imaging methods.

[0055] Ultrafast ultrasound imaging is distinguished from so-called conventional ultrasound imaging.

[0056] Conventional imaging is based on the focusing of ultrasonic waves by applying delay laws to elementary ultrasonic transducers at transmission. The same method is applied at reception to reconstruct the acoustic image received by the network of ultrasonic transducers. In other words, delay and summation processing is applied to obtain the desired focusing at transmission and reception.

[0057] Ultrafast imaging consists of insonifying (acoustically exciting) the entire medium using multiple unfocused acoustic waves (for example plane or divergent waves). The system records the electrical response signals generated by all the elementary transducers during an acquisition time window, then, from these signals, reconstructs the resulting image for a large number of focal points, until sufficient information is obtained on the body studied.

[0058] Ultrafast ultrasound imaging makes it possible to observe very rapid phenomena (typically 1000 images / second) at the cost of numerous calculations. It is complementary to conventional imaging which makes it possible to obtain equivalent image quality with much less calculation but also a slower image rate (typically 50 images / sec).

[0059] Micro-beamforming allows to reduce the number of response signals to be processed, and is based on conventional delay and summation imaging algorithms applied at the scale of elementary groups 113 of transducers, also called sub-apertures. The electrical signals generated by the elementary transducers 111 of each elementary group or sub-aperture 113 are delayed and summed by the elementary analog micro-beamforming circuit 123 of the group, embedded in the probe. This summation makes it possible to have only one output data transmission conductor between each elementary group 113 and the imaging system. The system can then reconstruct the image seen by the probe by applying new delay and summation processing to the signals produced by the micro-beamforming circuits 123, that is to say on macro-elements each corresponding to an elementary group 113.In other words, unlike a so-called fully populated probe (i.e. in which the set of individual response signals of the elementary transducers is transmitted to the system), in a micro-beamforming probe of the type described in relation to [Fig.l], the delay and summation processing is carried out in two stages, a first stage in the probe and a second stage outside the probe.

[0060] In the example of [Fig.l], the elementary transducers 111 have a square shape, and the sub-openings or elementary groups 113 also have a square shape.

[0061] The inventors have identified that depending on the type of images that one seeks to acquire, it may be advantageous to provide micro-beam-forming circuits coupled to elementary groups of ultrasonic transducers of different geometries.

[0062] In particular, we can distinguish between cases where we seek to acquire a two-dimensional image of the body to be analyzed (2D imaging) and cases where we seek to acquire a three-dimensional image of the body studied (3D imaging).

[0063] In 3D imaging, it is preferable that the distribution of the elementary groups is as isotropic as possible, that is to say that the inter-elementary group pitch 113 is the same or substantially the same in the direction of the rows and in the direction of the columns of the matrix of elementary transducers 111.

[0064] In this respect, the choice of a square sub-matrix of n*n elementary transducers as described in relation to [Fig.l] is an interesting solution.

[0065] However, in certain cases, the miniaturization capabilities of the electronics embedded in the probe can make it possible to produce micro-beam-forming circuits 123 capable of addressing a number of reception channels other than a square number. In this case, it may be interesting, in order to exploit all of the channels of each micro-beam-forming circuit, to define elementary groups 113 of non-square shape or elementary transducers 111 of non-square shape.

[0066] Thus, according to one aspect of an embodiment, an ultrasonic probe is provided incorporating electronic micro-beam-forming circuits of the type described in relation to [Fig.l], differing from the probe of [Fig.l] by the geometric construction of the elementary groups 113 of ultrasonic transducers 111.

[0067] Non-limiting examples of patterns of the elementary groups 113 of such a probe are illustrated in FIGS. 2, 3, 4 and 5.

[0068] In Figures 2, 3, 4 and 5, the direction of the rows of the matrix of elementary transducers 111 has been represented by an R axis and the direction of the columns of the matrix of elementary transducers 111 has been represented by a C axis.

[0069] In each of Figures 2, 3, 4 and 5, only a set of 2*2 elementary groups 113, respectively referenced 113(1), 113(2), 113(3) and 113(4) has been shown. In practice, the illustrated pattern can be repeated identically over the entire matrix of elementary transducers 111.

[0070] In the examples of figures 2, 3, 4 and 5, the number of adjacent elementary transducers 111 per elementary group 113 is equal to 18. The embodiments described are of course not limited to this particular case.

[0071] The elementary groups 113 have, for example, nested shapes in the direction of the rows and / or in the direction of the columns, for example as illustrated in relation to FIGS. 2, 3 and 4.

[0072] By nested shapes in the direction of the rows, it is meant that at least one subset of first and second elementary groups 113 adjacent in the direction of the rows comprises at least one column comprising elementary transducers 111 belonging to the first elementary group and transducers 111 belonging to the second elementary group.

[0073] By nested shapes in the direction of the columns, it is meant that at least one subset of first and second elementary groups 113 adjacent in the direction of the columns comprises at least one row comprising elementary transducers 111 belonging to the first elementary group and transducers 111 belonging to the second elementary group.

[0074] Two adjacent elementary groups 113 have, for example, symmetrical shapes with respect to an axis parallel to the direction of the rows or parallel to the direction of the columns.

[0075] By way of example, each elementary group 113 of ultrasonic transducers has at least one dimension in the direction of the rows, different from a dimension in the direction of the columns.

[0076] [Fig.2] illustrates a first exemplary embodiment in which the elementary groups 113 have head-to-tail L shapes, nested in the direction of the rows.

[0077] [Fig. 3] illustrates a second exemplary embodiment in which the elementary groups 113 have head-to-tail F shapes, nested in the direction of the rows.

[0078] [Fig.4] illustrates a third exemplary embodiment in which the elementary groups 113 have nested cross shapes, the main branches of which are respectively parallel to the direction of the rows and to the direction of the columns.

[0079] As a variant, the elementary groups 113 have a square shape, and the elementary transducers 111 each have an elongated shape in the direction of the rows or columns, for example a rectangular shape.

[0080] [Fig. 5] illustrates an exemplary embodiment in which the elementary transducers 111 each have a generally rectangular shape, the largest side of the rectangle (length) being parallel to the direction of the columns and the smallest side (width) of the rectangle being parallel to the direction of the rows. In this example, each elementary group 113 comprises a sub-matrix of n*m elementary transducers 111, n being the number of rows of the sub-matrix and m being the number of columns of the sub-matrix, n and m being chosen so that the elementary group 113 has a generally substantially square shape.

[0081] More particularly, in the example of [Fig.5], each elementary transducer has a length approximately equal to twice its width, and m is equal to twice n (n = 3 and m = 6 in the example shown), so that the elementary group 113 has a substantially square general shape.

[0082] 2D ultrafast imaging can consist of a reconstruction of a single plane after having insonified the entire medium. The image can be optimized by using, at emission, a delay law allowing the energy to be concentrated in the plane to be imaged. For example, a divergent or planar delay law is used for the plane to be imaged and focused perpendicular to this plane, for example a delay law in the shape of a horse's saddle. At reception, only the plane to be imaged is reconstructed. The return wave is focused perpendicular to the plane to be imaged. An example of such an imaging mode is for example described in the document entitled "3D ultrafast echocardiography: toward a quantitative imaging of the myocardium" - Victor Finel - Université Sorbonne Paris Cité, 2018, in particular in section 2.3.1.1 of this document.

[0083] In this case, it is advantageous for the inter-elementary group pitch to be as close as possible to that of a linear probe in the direction of the plane to be imaged.

[0084] Thus, according to one aspect of an embodiment, each elementary group 113 is made up of adjacent elementary transducers 111 of the same and unique row or column of the matrix of elementary transducers.

[0085] Figures 6, 7 and 8 schematically illustrate examples of 2D ultrasound imaging probes according to this embodiment. In these examples, the probe is particularly suitable for imaging one or more planes parallel to the direction of the rows of the matrix.

[0086] In the examples of figures 6 and 7, the elementary transducers 111 each have a square shape.

[0087] In the example of [Fig.6], each column of the matrix of elementary transducers 111 defines an elementary group 113. In other words, each elementary group 113 is made up of all the elementary transducers 111 of the same column of the matrix.

[0088] In the example of [Fig.7], each column of the matrix of elementary transducers 111 comprises several elementary groups 113, two elementary groups 113 referenced respectively 113(1) and 113(2) in the example shown. Each elementary group 113 is constituted by a set of adjacent elementary transducers 111 of the same column of the matrix.

[0089] The example of [Fig.8] is similar to the example of [Fig.6], except that, in the example of [Fig.8], the elementary transducers 111 each have an elongated direction in the direction of the columns, for example a rectangular shape, for example of the type described in relation to [Fig.5].

[0090] The embodiment of [Fig.8] can of course be combined with the embodiment of [Fig.7].

[0091] [Fig.9] schematically and partially represents another example of a rea Use of an ultrasound imaging probe according to one embodiment.

[0092] In this example, the probe is adapted to image one or more planes parallel to the direction of the rows of the matrix, and one or more planes parallel to the direction of the columns of the matrix.

[0093] This example schematically shows elementary groups 113 of 3 elementary transducers 111 each. The embodiments described are of course not limited to this particular case.

[0094] In the example of [Fig.9], each elementary transducer belongs to two and only two elementary groups 113(C) and 113(R). The first elementary group 113(C) consists of a set of adjacent elementary transducers from the same column of the matrix of elementary transducers 111, and the second elementary group 113(R) consists of a set of adjacent elementary transducers from the same row of the matrix.

[0095] By way of example, each first elementary group 113(1) is made up of all the elementary transducers 111 of the corresponding column, as described in relation to [Fig.6]. As a variant, each first elementary group 113(1) is made up of a subset of adjacent elementary transducers 111 of the corresponding column, as described in relation to [Fig.7]. Similarly, each second elementary group 113(2) may be made up of all the elementary transducers 111 of the corresponding row, or of a subset of adjacent elementary transducers 111 of the corresponding row.

[0096] In [Fig.9], a dedicated micro-beam-forming circuit 123 (pBF) connected to the elementary transducers of the group is also schematically represented for each elementary group 113. For the sake of simplification, the reception circuits 121 ([Fig.1]) connected to the elementary transducers 111 have not been detailed in [Fig.9].

[0097] Thus, in the example of [Fig.9], each elementary transducer 111 is connected to two and only two micro-beam-forming circuits 123.

[0098] [Fig. 10] schematically and partially represents another example of an embodiment of an ultrasound imaging probe according to one embodiment.

[0099] The example of [Fig. 10] differs from the example of [Fig.9] essentially in that, in the example of [Fig.10], the same micro-beamforming circuits 123 are pooled and shared by the elementary groups 113(R) and by the elementary groups 113(C).

[0100] More particularly, in this example, each micro-beamforming circuit 123 is shared by one and only one elementary group 113(R) and one and only one elementary group 113(C) elementary 113(R).

[0101] For this, a multiplexing circuit MUX makes it possible to connect to the input terminals of the circuit 123 either the elementary transducers 111 of the associated elementary group 113(R), or the elementary transducers 111 of the associated elementary group 113(C).

[0102] Thus, the number of micro-beamforming circuits is halved compared to the example in [Fig.9].

[0103] Figures 11 and 12 represent other examples of arrangements of the elementary transducers of an ultrasound imaging probe according to one embodiment.

[0104] The examples of Figures 11 and 12 relate to two-dimensional (2D) imaging probes. The probes of Figures 11 and 12 are more particularly so-called 1.75D type probes, i.e. matrix probes whose inter-transducer pitch in elevation, i.e. in the direction of the columns, is equal to several times the central wavelength X of the emitted ultrasonic waves, while the inter-transducer pitch in azimuth, i.e. in the direction of the rows, is between / . and X / 2.

[0105] The transition from a 1D probe (linear array of elementary transducers) to a 1.75D probe makes it possible in particular to improve its imaging capabilities in terms of: - variation of the size of the aperture and elevational acoustic apodization; - dynamic focusing in transmission and reception; - beam deflection outside the imaging plane to better discretize the reflectors.

[0106] In the examples of Figures 11 and 12, the probe comprises four elementary transducers per column, and 64 columns. The embodiments described are however not limited to this particular case.

[0107] In the examples of figures 11 and 12, the number of adjacent elementary transducers 111 per elementary group 113 is equal to 16. Here again, the embodiments described are not limited to this particular case.

[0108] In the example of [Fig. 11], each elementary group 113 is constituted by all the elementary transducers 111 of four adjacent columns of elementary transducers. Thus, in this example, the elementary transducers of the same column are connected to the same and unique micro-beam-forming circuit 123.

[0109] In the example of [Fig. 12], each elementary group 113 is constituted by all the elementary transducers of a sub-matrix of 2 adjacent rows by 8 adjacent columns of elementary transducers. Thus, in this example, each column comprises two adjacent transducers connected to a first micro-beamforming circuit 123 and two adjacent transducers connected to a second micro-beamforming circuit 123.

[0110] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will occur to those skilled in the art. In particular, the described embodiments are not limited to the specific examples of arrangement of the elementary groups 113 described in connection with FIGS. 2, 3, 4, 5, 6, 7, 8, 9 and 10.

[0111] Finally, the practical implementation of the embodiments and variants described is within the reach of those skilled in the art from the functional indications given above.

Claims

Claims

1. An ultrasonic imaging probe (100) comprising a plurality of elementary ultrasonic transducers (111) arranged in a matrix in rows and columns, the probe comprising, for each elementary ultrasonic transducer (111), a specific receiving circuit (121) connected to an electrode of the transducer and adapted to amplify an electrical response signal generated by the elementary transducer (111) during a phase of reception of an ultrasonic wave, in which the elementary transducers (111) are distributed into several elementary groups (113) each comprising a plurality of transducers (111), the probe comprising, for each elementary group (113), an analog micro-beamforming circuit (123) individually connected to an output terminal of the receiving circuit (121) of each transducer (111) of the group (113),and adapted to provide an analog signal generated by delay and summation of analog output signals from the reception circuits (121) of the elementary transducers (111) of the group (113), in which each elementary group (113) consists of a set of adjacent elementary transducers (111), said set having at least one dimension, in the direction of the rows, different from a dimension, in the direction of the columns, or in which the elementary transducers (111) each have an elongated shape in the direction of the lines or columns, and each elementary group (113) consists of a set of adjacent elementary transducers (111), said set having a generally square shape.,

2. Probe (100) according to claim 1, in which each elementary group (113) comprises a number of elementary transducers (111) different from an integer squared.

3. Probe (100) according to claim 1 or 2, in which the elementary groups (113) have nested shapes.

4. Probe (100) according to claim 3, in which the elementary groups (113) have nested head-to-tail L shapes, or nested head-to-tail F shapes.

5. Probe (100) according to claim 3, in which the elementary groups (113) have nested cross shapes.

6. The probe (100) of claim 1 or 2, wherein each group elementary (113) consists only of adjacent elementary transducers (111) of the same row or the same column of the matrix of elementary transducers.

7. Probe according to claim 6, in which each column of elementary transducers (111) of the matrix of elementary transducers comprises several elementary groups (113) each comprising a plurality of adjacent elementary transducers (111) of the column, and / or each row of elementary transducers (111) of the matrix of elementary transducers comprises several elementary groups (113) each comprising a plurality of adjacent elementary transducers (111) of the row.

8. Probe (100) according to claim 6 or 7, in which each elementary transducer (111) belongs to only a first elementary group (113(R)) consisting only of elementary transducers (111) of the same row of the matrix of elementary transducers, and a second elementary group (113(C)) consisting only of elementary transducers (111) of the same column of the matrix of elementary transducers.

9. Probe (100) according to any one of claims 1 to 7, in which each elementary transducer (111) belongs to a single elementary group (113).

10. A probe (100) according to any one of claims 1 to 9, wherein each receiving circuit (121) comprises an amplifier (121a) and a gain time adjustment circuit (121b) between said transducer electrode and an input terminal of the microbeamforming circuit (123).

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